Heretofore, various elastomers otherwise having low green strength have been improved by adding various types of chemical additives thereto. In other words, at least one additional component was added. Such compositions were homogeneous and substantially uncured.
The present invention is readily distinguished in that a heterogeneous rubber composition is made from chemically similar blends and no other compounds or additives are utilized.
Regarding various different elastomer blends containing carbon black therein, they have been mixed with each other with respect to investigating various chemical and physical properties. For example, an article "Carbon Black Distribution in Elastomer Blends" by Hess, Scott, and Callan, Rubber Chemistry and Technology, pages 371 through 383, Volume 40, 1967, discusses the degree of subdivision of different polymer systems and the distribution of reinforcing filler particles between the phases.
Elastomer Blends, Compatibility and Relative Response to Fillers by Callan, Hess and Scott, page 815-837, Rubber Chemistry and Technology, 1971, relates to zone size variations among different polymer blends, compatibility of butadiene rubber and styrene-butadiene rubber, filler distribution between separate polymer phases as influenced by fundamental polymer and filler characteristics and carbon black transfer.
The article, Effect of Heterogeneous Carbon Black Distribution on the Properties of Polymer Blends by Sircar, Lamond, and Pinter, pages 48-56, Rubber Chemistry and Technology, 1974, relates to comparisons of varying compatibility, for example, styrene-butadiene rubber and polybutadiene rubber, styrene-butadiene rubber and natural rubber, polybutadiene rubber and natural rubber, and polybutadiene rubber and chlorobutyl rubber. Further, the article, Elastomer Blend Properties-Influence of Carbon Black Type and Location, by Hess and Chirico, page 301-326, Rubber Chemistry and Technology, Vol. 50, 1977, relates to the study of various blends of different types of rubber and their performance as affected by carbon black.
Finally, the article Experimental Studies of the Relationship of Processing to the Crack Growth of Carbon-Black-Loaded SBR-Cis-Polybutadiene compounds by Biing-lin Lee, Journal of Applied Polymer Science, Vol. 27, page 3379-3392 (1982), relates to multi-component polymer systems which are blended together to achieve improved results.
However, none of these articles relates to or suggests the blending of any chemically similar or identical compounds to yield different and unexpected results such as improved green strength.